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    <title>AATSR Regridding Processor</title>
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<table class="header">
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        <td class="header">Algorithm Specification</td>
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<h3>Algorithm Specification</h3>
<p>This tool parses an (A)ATSR(-1/2_ ATS_TOA_1P product, then for each pixel in the Nadir and Forward views:<br>
<ol>
    <li>Computes the original geolocation of the measurement (UBT) using methodology taken from a Technical Note by
        Andrew Birks of Rutherford Appelton Laboratory -
        <a href="https://earth.esa.int/pub/ESA_DOC/ENVISAT/AATSR/Instrument_Pixel_Coordinates_and_Measurement_Time.pdf">
            "Instrument Pixel Coordinates and Measurement Times from AATSR Products"</a> -
        and methodology extracted from <a href="https://earth.esa.int/instruments/aatsr/faq/AATSR_FAQ_issue1.pdf">
            the AATSR Frequently Asked Questions (FAQ) document "Appendix A Interpolations of pixel geolocation in AATSR
            full resolution products"</a> . </li>
    <li>Computes the acquisition time of the pixels using the Andrew Birks TN.
        This methodology allows retrieval of the acquisition time on a pixel basis as opposed to the usual per scan basis.
        Note that there appears to be a systematic bias of +0.15 seconds in the acquisition time retrieval.
        This is hinted at in the Andrew Birks TN.</li>
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